I have a quick question for my English speaking fiends :

In the AARC guideslines for weaning from a ventilator, they mention: "SBT" for spontaneous breathing trial; do they mean with pressure support , or not.

If not, why do they suggest a SBT for 30 to 120 minutes. Sounds excessive... W'ont patients "choke" on there extrinsec resistances (ET tube, connectors, HME, ...)

Thank you for any info that would help me comprehend thoses guidelines.

In my opinion, SBT would be tube compensation with +5 PEEP.

GJ

Renton,
To my knowledge SBT means T-Piece trials. The idea is to get total freedom from the machine.
Please anyone else feel free to correct me if I am wrong.

Thanks to GJ and Bill C for the posts. Still, the AARC guidelines: with or without PS?

GJ: If Tube compensation is not an option on your vent (eg: the Servo i), do you "build" yourself an equation to set up PS according to Raw ext (I know, ATC only delivers a PS during the beginning of the breath, and usual PS if stable during the inspiratory time, but, Maquet doesn't want do put it in their vent...)

Bill C: Personnaly, the only time that I use T piece (free O2) is with either neurological type of problems , or haemodynamic problems (hydrostatic pressur (and/or preload) believed to be too high, risking pulmonary oedema). My question: do you always use SBT (as you understand it) in all of your patients to decide on extubation?

To all: thank you for your posts!

I do believe SBT is considered to be T-piece in most articles. I would say ATC(to overcome resistance of the ETT) and small amounts of peep(+5) would reflect more of what the patient would do off the vent(electronic extubation).


GJ

SBT is T tube or for trach patients a trach collar to bland aerosal. No positive pressure of any kind !

In my opinion, if your vent doesn't have tube comp. I would wean with PSV+5-8,PEEP+5. I have noticed when weaning with ATC only and +5PEEP my pip's are 6-12. If I'm getting it right the Tube comp being given is 1-7 based on pip's 6-12. FYI, I am using a Drager Evita XL. Also, SBT is considered T-piece/T-collar, but I wouldn't go that route with the availablity of todays vents.

Hope this helps,

GJ

SBT is not the same as a trach hood trial and only refers to patients with an endotracheal tube and use used as a tool to assess readiness for extubation.

A SBT can be 't-piece' or on the ventilator. On the ventilator typical settings are CPAP=5 & PS=0, or CPAP=5 & PS=5, or ATC. There has been some studies that have compared T-piece to CPAP=5 PS=5 when doing a SBT and there is no difference.

As for the duration of the SBT, 120 mins was first studied and deemed to be an appropriate time to assess a patients readiness for extubation but some studies have found no difference in failure rates if the patient was only on a SBT for 30 mins compared to 120 mins. So it is now generally accepted that the duration for an SBT be at least 30 minutes and need not be longer than 120 minutes.

Also, SBTs need only be done once a day, if a patient fails, they will fail again if tried later that same day. This is also evidence based. So you are better off waiting till the next day till repeating a SBT. It has been shown that a patient's fatigued diaphragm can take 24-48 hours to recover from a failed SBT.

When daily SBTs are performed on patients that meet criteria for a SBT, they are liberated from the ventilator sooner than patient who has only physician directed weaning.

I typically use CPAP=5 PS=5 for SBTs, except with patients where even a little bit of CPAP can make a large difference, these patients are typically patients with bad CHF or COPD. In these patients I will T-piece them to eliminate all PPV.

I have some articles that discuss SBTs around somewhere, if you would like more info please let me know.

Jeffd
http://resptherapy.com

The following link is one of many that describes the various techniques for performing an SBT. It was written by Dr. Dean Hess...

Another researches that has published some great work on SBTs is Esteban et al.

http://www.chestjournal.org/cgi/reprint/120/6_suppl/474S.pdf

[QUOTE]Originally posted by JeffD:
[b]SBT is not the same as a trach hood trial and only refers to patients with an endotracheal tube and use used as a tool to assess readiness for extubation.

I'am having difficulties to translate that part: "trach hood trial "; could you specify.

Thank you

ps: I do entirely agree on the "once a day SBT", we see oftenly unexperiences professionnals trying 3 or for times a day (rending the patient unable to breath by himself for days...)

However, you suggest that SBT for 2 hours do not have any repercussion on re-intubation , is that with ps (5 ou ATC) or without. I did view a few articles saying the same thing, but, in my daily practice, I find that patient, after 15 to 30 minutes of ATC (or equivalent) with peep +3 or +5 , with all other spheres of weaning acceptables (heamodynamics, neurological, nutritionnal, etc), is enough. But I do have to say that rougly 20-30% of or patients need NPPV after extubation (which we fing more acceptable than a ET tube).

That could be "treated" in another tread...